Amanda Knox, the US college student cleared of murder by an Italian court after four years in prison, is to talk publicly about the case for the first time.

Knox, 25, will discuss the sensational case with journalist Diane Sawyer in an interview to be broadcast on April 30 - the same day her book Waiting to Be Heard is published, TV network ABC said.

Knox, along with her then boyfriend, Raffaele Sollecito, was convicted of murdering her British roommate, Meredith Kercher, in 2007 in a grisly, sex-fueled crime in the Italian hill town of Perugia. She was sentenced to 26 years in prison.

She was cleared on appeal in 2011 and returned from Italy to her Seattle-area home, where she has kept a low profile.

Kercher's half-naked body, with more than 40 wounds and a deep gash in the throat, was found in the apartment she shared with Knox in Perugia where both were studying.

The crime and the trial drew worldwide attention and criticism in the US of the Italian legal system.

ABC said Knox would divulge details she had never shared about her journey from an American student studying abroad to a young woman facing decades behind bars in Italy.

Sollecito released his own book, Honor Bound, last year. He acknowledged that their sometimes bizarre behavior after Kercher's killing gave police reason for suspicion.

Rudy Guede, a petty criminal who was convicted separately, remains imprisoned and is serving a 16-year-sentence.